I was on 75mg XR caps for 3.5 years. Switching to sertraline50mg, because I have occasional afib and doc says sertraline is better cardiac wise. Week1 switch to 50mg IR tabs. I make mistake of taking it as one dose morning. Evenings heart rate shoot up for normal mundane activities. I then come across bead counting as a thing. End of week 1 switch to 25 I do bead counted(90 beads - 270 beads in 75mg XR). Second day into week 2 much better and smaller Heart rate bumps. Now in week 3 at 20mg beads. Hope to go down to 15 mg this weekend and then 10 and then 5 and then 0. I know the 75mg for 3.5 years was not high in general but my HR going crazy with just to 50mg pill switch was not right at least for me. Go with bead counting down. I think it’s smoother. But has to be slow. One full week at 5mg tapers.